Nephrolithiasis, commonly called kidney stones, is a growing pandemic. In industrialised countries, it is estimated that prevalence ranges between 4% and 20%. The aetiology and pathogenesis of nephrolithiasis is complex and multifactorial. Despite of these facts, limited information is available on a range of factors concerning the condition in sub-Saharan Africa. On consideration of several factors including climatic conditions and the number of positive diagnosis of kidney stones at the main referral laboratory (an average of 15 cases per day); it can be asserted that nephrolithiasis is a significant problem in the country Eritrea.
Objective: The aim of this study was to evaluate kidney stone composition and potential risk factors in patients presenting with nephrolithiasis at Orotta Referral Hospital.
Methods and Materials: This was a cross-sectional matched case-control study. The study cohort consisted of 154 nephrolithiasis patients, meeting a pre-set criterion. Presence of kidney stones was confirmed using renal ultrasonography or plain abdominal radiography. The control group consisted of 154 respondents, with no kidney stone, matched for sex and region of residence. Urine samples were collected from individuals with kidney stone for microscopic analysis of stone composition. Dietary and other risk factors for kidney stone were evaluated using an interviewer administered questionnaire with a non-standardised component and a standardised Food Frequency Component.
Results: Microscopic analysis of urine samples indicated that Calcium oxalate (51.7%) was the most common stone type. Uric acid (21.7%), amorphous urate (13.3%) and amorphous phosphate (3.3%) were also indicated. In the multivariate logistic analysis, the data indicates that risk factors for nephrolithiasis included: family members with kidney stone (OR =0.414, 95% CI =0.046-434, p =0.001); previous residency in the hot regions of the country (OR =0.419, 95% CI =0.199-883, p =0.022); daily consumption of green vegetables (OR =0.054, 95% CI =0.016-0.183, p =0.000); Intake of less than 1 litres if water a day (OR =0.396, 95% CI =0164-0.958, p =0.04) and working as a labourer (OR =0.345, 95% CI =0.152-0.782, p =0.011).
Conclusions: Based on the study results, it can be concluded that calcium oxalate is the most common type of kidney stone. The risk factors include infrequent intake of water, daily consumption of green leafy vegetable, hard labor, living in hot environment and family members with kidney stone.